This post explains for the semiconductor D1138.
The Full Part Number is 2SD1138. The package is TO-220AB.
The function of this semiconductor is NPN transistor.
The manufacturers of this product is Hitachi Semiconductor.
See the preview image and the PDF file for more information.
Preview images :
Low frequency high voltage power amplifier TV vertical deflection output complementary pair with
Absolute Maximum Ratings (Ta = 25°C)
1. Collector to base voltage : VCBO = 200 V
2. Collector to emitter voltage : VCEO = 150 V
3. Emitter to base voltage : VEBO = 6 V
4. Collector current : IC = 2 A
5. Collector peak current : IC (peak) = 5 A